I've got this old 8-bit ISA card on my
"interesting to try out" list.
Corvus had a videotape backup and then later a device called the Bank,
but the processing for what hardware I saw was "dumb" just support
logic. The cpu of the PC did the heavy lifting.
The Bank used a corvus network node, I think to communicate, so there
was only a corvus net card in the backup server and software to support
the bank hardware.
I think Alpha Micro had a product too. Their surplus showed up here in
Orange County for a while when they crashed and burned but no software,
sorry, also they had no coprocessor either.
And a little higher up on the mini scale, Digidata had a product called the
"Gigastore" that was a VHS tape unit interfaced by a Q-bus card and a variant
of the Pertec Formatted (two 50 pin cable) tape interface popular for 9-track
and some other drives. I used and recovered data from these way back in the
90's.
Tim.